Narrow-leaved Everlasting Pea

Lathyrus sylvestris
© Copyright: Jouko Lehmuskallio
  • Name also

    Flat pea

  • Growing form

    Perennial herb.

  • Height

    50–180 cm (20–70 in.). Stem limp, flat, widely winged, glabrous.

  • Flower

    Corolla zygomorphic, red, 13–20 mm (0.52–0.8 in.) long, Petals 5; the upstanding the ‘standard’, the lateral two the ‘wings’, the lower two united to form the ‘keel’, overall shape of corolla being butterfly-like. Calyx 5-lobed. Stamens 10. A single carpel. Inflorescence long-stalked, 3–10-flowered raceme.

  • Leaves

    Alternate, stalked, stipulate. Leaf-stalks narrowly winged. Blade pinnate, 1-pairs, terminal leaflet modified into a tendril. Leaflets lanceolate–narrowly ovate, 5–15 cm (2–6 in.) long, with entire margins. Stipules narrower than stem.

  • Fruit

    40–70 mm (1.6–2.8 in.) long, brown, 5–15-seeded (pod) legume.

  • Habitat

    Rich hillside forests, forest margins, hedgerows, roadsides and embankments, waste ground.

  • Flowering time

    July–August.

Narrow-leaved everlasting pea is one of the most handsome pea plants. Its 2-metre (6.5 feet) stem lies on the ground or climbs up low trees and bushes and trees’ lower branches. It uses its prehensile organs to climb, and it has more tendrils than its other Finnish relatives. Both the terminal leaflet and uppermost pair of leaflets have evolved into tendrils, so there is only one pair of leaflets left – and in extreme situations there are only tendril-like branches.

Narrow-leaved everlasting pea’s ornamental flowers and special stem structure easily catch the eye of even casual passers-by. The species favours fairly abundant nutrition, light and heat in sparse broad-leaved hillside forests and dry hillside meadows, where it looks exotically southern. The species looks like its close southern European relative sweet pea (L. odoratus), which is a common sight in Finnish gardens. It is grown as an ornamental, but it sometimes escapes into the wild.

Distribution map: Lampinen, R. & Lahti, T. 2021: Kasviatlas 2020. Helsingin Yliopisto, Luonnontieteellinen keskusmuseo, Helsinki.